1,1,1-trisubstituted-2-cyanohydrazinium hydroxide, inner salts and the preparation thereof

ABSTRACT

1,1,1-Trisubstituted-2-cyanohydrazinium hydroxide, inner salts, obtained by reaction of tertiary amines and cyanogen azide, useful as dispersing agents for suspending solids in aqueous media and as intermediates for producing buffering agents are claimed.

United States Patent Inventor Appl. No.

Filed Patented Assignee Frank Dennis Marsh Wilmington, Del.

Mar. 5, 1970 Nov. 30, 197 l E. l. du Pont de Nemours and Company Wilmington, Del.

Continuation-impart of application Ser. No.

663,212, Aug. 25, 1967, now abandoned. This application Mar. 5, 1970, Ser. No. 16,951

1,1 ,1-TRlSUBSTITUTED-Z-CYANOHYDRAZINIUM HYDROXIDE, INNER SALTS AND THE PREPARATION THEREOF 7 Claims, No Drawings US. Cl

Primary ExaminerHenry R. Jiles Assistant Examiner-Harry l. Moatz Atlorney-D. R. J. Boyd ABSTRACT: I ,1 ,1-Trisubstituted-2-cyanohydrazinium hydroxide, inner salts, obtained by reaction of tertiary amines and cyanogen azide, useful as dispersing agents for suspending solids in aqueous media and as intermediates for producing buffering agents are claimed.

RELATED APPLICATIONS This application is a continuation-in-part of application Ser.

No. 663,212 filed Aug. 25, 1967, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to inner salts of l,l,l-trisubstituted-2- cyanohydrazlnium hydroxide and to the preparation thereof from cyanogen azide and a tertiary amine.

WARNING: Cyanogen azide, a reactant in this invention, is

explosive when free or nearly free of solvent and should 5 be handled with great care. It can be used, however, with comparative safety in dilute or moderately concentrated solution.

SUMMARY OF THE INVENTION This invention is directed to a zwitterionic compound of the formula Il -N 1' 2 wherein R, R and R are as described above. These zwitterionic compounds are useful as dispersing agents for suspending solids in aqueous media and as a intermediates for producing buffering agents.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A. Composition of matter The zwitterionic compounds of this invention represented by formula I are called N,N,N-trisubstituted aminocyanoimides or l,l,ltrisubstituted-2-cyanohydrazinium hydroxide,

inner salts (see Rules 276-280 of the Naming and Indexing of Organic Compounds, Chemical Abstracts, Vol. 56, pg. 45N). These compounds are generally colorless, solid or high-boiling-liquid products. The zwitterionic structure is stable in acidic aqueous reagents which are capable of converting the cyano group into an amide group. Hydrolysis of the compounds of this invention yield l,l,ltrisubstituted ureido ammonium salts, especially the chlorides, having the formula These carbonyl derivatives react with ammonia to form ammonium salts which are bufiering agents.

In the compounds of this invention, R is alkyl of up to [0 carbons and cycloalkyl of four to six carbons, and R and R, taken separately are alkyl of up to 10 carbons, phenyl, naphthyl or cycloalkyl of four to six carbons. For example, within the definition of R, R or R is included: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, isopentyl, hex- 10 yl, heptyl, octyl, nonyl, decyl, cyclobutyl, cyclopentyl,

cyclohexyl, and the like. Additionally, R and R taken together, can be 1,4-butylene, l,5-pentylene, and l,6-hexylene and R, R and R taken together is CH=CH-CH lCH-CI-l The compounds wherein R is alkyl and R and R are phenyl or alkyl are preferred. The compounds wherein R, 'R and R are alkyl are most preferred.

B. Process The l l l -trisubstituted-2-cyanohydrazinium hydroxide, inner salts, of this invention are obtained by heating a tertiary amine with cyanogen azide at temperatures of 0-l00 C. preferably in an inert solvent. Gaseous nitrogen is liberated in the course of the mildly exothermic reaction.

The reactants are normally brought together at room temperature and allowed to react spontaneously, preferably at a temperature of 25-50 C. Inert solvents, such as aliphatic nitriles, e.g., acetonitrile, aromatic nitriles, e.g., benzonitrile, aliphatically saturated hydrocarbons or halohydrocarbons, e.g., hexane, cyclohexane, benzene, toluene, methylene chloride, ethyl bromide, chlorobenzene and the like or esters, e.g., ethyl acetate, methyl benzoate and the like, can be used as a diluent and as a safety precaution for the handling of cyanogen azide. However, the reaction can be conducted without added solvent.

The process can be conducted in a batch or continuous-flow process. The process is conveniently conducted at atmospheric pressure but can also be conducted at subatmospheric or superatmospheric conditions. The reaction time required for the process can be 1-4 hours or shorter or up to 10-20 hours or longer.

Cyanogen azide is produced by the reaction of a cyanogen halide with an alkali-metal halide in an organic solvent such as acetonitrile or methylene chloride. Cyanogen azide is described in my copending coassigned application Ser. No. 215,800, filed Aug. 9, 1962 and in J. Am. Chem. Soc., 86, 4506( 1964).

The tertiary-amine reactants are well known, readily available compounds (See Wagner and Zook, Synthetic Organic Chemistry, John Wiley and Sons, Inc., New York, 1953, pp. 653-727). Tertiary-amine reactants which can be used in the process of this include methyldiethylamine, ethyldimethylamine, tripropylamine, tributylamine, methyldibutylamine, dipentylethylamine, dihexylmethylamine, octyldimethylamine, di-n-octylmethylamine, tri-n-octylamine, di-ndecylmethylamine, di-n-decylbutylamine, N-methyl pyrrolidine, N-decylpyrrolidine, N-methylpentamethylenimine, N-decylhexamethylinimine, cyclohexyldimethylamine, cyclopentyldimethylamine, cyclobutyldimethylamine, cyclohexyldecylmethylamine, cyclobutyldimethylamine, cyclohexyldecylmethylamine, cyclohexylphenylmethylamine, cyclohexyl-a-naphthylmethylamine, N-ethylhexamethylinime, N-methylhexamethylenimine, N-methylpentamethylenimine, N-octylpyrrolidine N-propylpyrrolidine, N-ethylpentamethylenimine, phenyldimethylamine, diphenylmethylamine, diphenyldecylamine, naphthyldimethylamine, dinaphthylmethylamine, dinaphthylbutylamine, naphthyl didecylamine, pyridine and the like.

The following examples further illustrate the invention.

EXAMPLE l A. Cyanogen azide (0.22 mole) dissolved in acetonitrile (total solution volume 84 ml.) was added with stirring during 50 minutes to a large excess of triethylamine (1000 ml., -723 g., 7.2 moles). The temperature rose spontaneously from 24-36.5 C., nitrogen ("0.18 mole) was liberated, and an oil separated. The mixture was stirred and heated at 4062 C. for an additional 6 hours. The oil was separated, taken up in acetonitrile (total solution volume 290 ml.) and filtered. A 50 ml. aliquot of this filtrate was evaporated to dryness (50 C./0.2 mm.) to give a brown oil (4.9 g., 92 percent). An aliquot of the residual oil was dissolved in methylene chloride, passed through a Zk-inch bed of magnesia-silica gel, and the eluant evaporated to dryness (25 C./0.l mm.) to give the product as a crystalline solid which was sequentially recrystallized once from a mixture of tetrahydrofuran and ether and twice from tetrahydrofuran to give white needles, m.p. 87.7"89.4 C.

(deutertoacetomtnlc solution.

telramethylsilane Internal standard) H n m r. spectrum (saturated C-H).

Infrared spectrum 334g. 3 441.1.

B. To a flask equipped with a magnetic stirrer, thermometer, dropping funnel, and condenser (the exit of which was connected to a wet-test meter) was added cyanogen azide (0.22 mole) dissolved in toluene (total volume 15] ml.). The solution was stirred and cooled (23 C.) while triethylamine (22.3 g., 0.24 mole) dissolved in toluene (I ml.) was added during 30 minutes. Nitrogen (-02 mole) was liberated during l7 hours at 23-25 C., and the light tan crystals separated. The mixture was filtered and the filter cake washed with ether and dried (28.2 g., 9l percent). The filtrate was evaporated to dryness to give additional product (465 g., percent). The main fraction (28.2 g.) was dissolved in methylene chloride, decolorized with carbon black and passed through a 3-inch bed of magnesia-silica gel. The eluant was concentrated, cooled, and diluted with ether to give white needles. These crystals were dissolved in acetonitrile and passed through activated alumina (Woelm Neutral Activity l The acetonitrile was removed from the eluant (l mm./25 C.) to give white needles which were recrystallized from tetrahydrofuran to give l,l,l-triethyl-2-cyanohydrazinium hydroxide, inner salt, m.p. 89.8-90.8 C.

Anal Calcd for C,H,,N

M W 142 lEhullloscopically tll chloroform) Found EXAMPLE 2 l l l -Trimethyl-2-Cyanohydrazinium Hydroxide, Inner Salt Toluene (200 ml.) was added to a flask equipped with a thermometer, magnetic stirrer, dropping funnel, gas inlet tube, and condenser (cooled at 78 C.) the exit of which was attached to a wet-test meter. Trimethylamine (27 g., 0.46 mole) was condensed into the flask. The flask was cooled at l5-24 C. while cyanogen azide (0.32 mole) in acetonitrile (total solution volume 205 ml.) was added during 2 hours. When addition was complete, the mixture was stirred at room temperature for a total of 17 hours, during which time nitrogen (03 mole) was liberated. The reaction mixture was filtered and the off-white crystalline solid dried (29 g.). The filtrate was evaporated to dryness to give additional product (total 32.5 g., percent). The combined product was dissolved in methylene chloride, decolorized with carbon black and filtered through a 3-inch bed of magnesia-silica gel. The eluant was cooled, diluted with ether and filtered to separate fine white needles of I,l,l-trimethyl-Z-cyanohydrazinium hydroxide, inner salt (m.p. l73.5-l76 C., 27.65 g., 86.5 percent).

A sample of crude product prepared in a similar manner by adding trimethylamine diluted with carbon tetrachloride to cyanogen azide prepared in acetonitrile was purified in the same way to give the product (m.p. l7 l-l72 C.

Anal. Calcd. for C H N C, 48.46, C, 48.72.

M.W ,99.l M.W., IOU, I04 (b.p. in acetone).

H, 9 l5. H, 8.90;

Found N, 42.02.

ldeuterioacetonitrile solution.

tetrarnethylsilane internal standard).

H n.m.r spectrum r Assignment Intensity l-Cyclohexyl-l l -Diethyl-2-Cyanohydrazinium Hydroxide, lnner Salt Cyanogen azide (0.18 mole) dissolved in toluene (total solution volume, 72 ml.) was added to N,N-diethylcyclohexylamine (24.9 g., 0.15 mole) during 15 minutes with stirring and cooling to keep the temperature at 2535 C. When addition was complete the mixture was stirred at room temperature for an additional l6 hours. Nitrogen, about 0.15 moles, was liberated. The reaction mixture was evaporated to dryness (30 C./l mm.) to give a brown viscous oil (31.5 g., 100 per cent).

This oil was dissolved in toluene, warmed with carbon black. filtered and the filtrate evaporated to dryness to give the product as a light straw-colored viscous oil.

Infrared spectrum 2 9 (possibly NH impurity); 3.4g,

3 s (CH); 3.8 4.0 4.5-4.7, (CN) H n m r spectrum (CDCL, solution, tetramethylsilune Internal standard) I 1 Assignment Intensity ininnnn 3.29 (complex group) N-CH, 4 5.17 (single peak} CN(tentative) I 5.2-7.5 (broad complex) Cyclic CH, '7 7.15 (triplet) CH EXAMPLE 4 l l l -Tri-n-Octyl-2-cyanohydraziniurn Hydroxide, lnner Salt Cyanogen azide dissolved in toluene (0.15 mole, total solution volume, 60 ml.) was added during 20 minutes to tri-n-octylamine dissolved in toluene (50 ml.). The reaction mixture was stirred and cooled to keep the temperature at 2438 C. After the initial exothermic reaction subsided, the mixture was stirred at ambient temperature for a total of 18 hours during which time nitrogen (0.1 mole) was liberated. The reaction mixture was filtered and volatile materials were removed from the filtrate (50 C./l mm.) to give a viscous brown oil (45 g.). The product was dissolved in toluene 150 ml.), warmed with carbon black and filtered. The filtrate was evaporated to dryness (60 C./l mm.) to give a viscous tan oil (38 g., 100 percent).

H n.m.r. spectrum: (CCl solution. tetramethylsilanc internal standard).

1 Assignment Intensity 3.90 CH,N' 2 732 CH, 12 8.18 CH,, 3

Infrared spectrum: A 3.4g, 3.48;. (CH); 4.5g. (CN).

EXAMPLE 5 N2 NaCN 45-55 N Tia N .CN

Cyanogen azide (0.1 18 mole) in acetonitrile (total solution volume 67 ml.) was diluted with pyridine (233 ml.) and the mixture stirred and heated at 49-55 C. for 5.5 hours. Nitrogen was liberated, and the reaction mixture became dark colored. Volatile materials were removed from the reaction mixture on a rotary evaporator (50 C./l mm.) to give a brown crystalline solid (13.1 g., 93.5 percent). An aliquot (4 g.) of this crude material was sublimed l40-180 C./0.l mm.) and resublimed (140 C./().lp.) to give pure white crystals of pyridine cyanoimide, m.p. l l9l20 C.

Anal. Calcd. for C,,N,N,: c, 60.49; C. 60.85;

Found:

A second aliquot of the crude product was dissolved in methylene chloride, decolorized with carbon black, passed through a short bed of magnesia-silica gel, and the eluant diluted with ether. White crystals separated (m.p. 120.6 to 122.6 C.).

Infrared spectrum: 3.22 (:CH); 4.69;. (CEN); 6. 19;,

6.76;. (conjugated cyclic C=C and/or C: N).

H n.m.r. spectrum: (dimethyl sulfoxide solution.

tetramethylsilunc internal standard The compounds of this invention and their hydrolysis products are useful as dispersing agents for suspending solids in an aqueous medium. The double pseudoureido tertiary-ammonium ammonium salts are buffering agents for both aqueous and organic media.

For example, a suspension of carbon particles was obtained when 0.5 g. of carbon black was added to 10 ml. of water containing 0.1 g. of the product of example 1 and the mixture was vigorously agitated. The same result was obtained when the experiment was repeated using 0.1 g. of the product of example 2 instead of the product of example 1. The carbon particles of a control experiment consisting of the carbon black and water settled rapidly.

The compounds of the present invention are useful for dispersing pigments in water-based paints such as latex paints. Thus, to 84 ml. water placed in a high-speed mixer was added 6 g. of (Cl-1 N NCN and 10 g. lampblack was then added slowly and the mixture was stirred for 2 minutes after addition was complete. A thick homogeneous suspension resulted. No water separated from this suspension after standing for 24 hours. Three parts of the resultant suspension was stirred into parts of a white water-based latex house paint (Lucite House Paint Du Pont 50C white) and the tinted paint was coated onto paper and dried. A dark grey, fairly uniform, coating was obtained. Essentially the same results were obtained when [CH (Cl-l N N CN is substituted for (Cl-l NNCN in the above. When 10 grams of lampblack is added to 84 ml. of water and agitated as in the above experiments a thin fluid suspension of carbon black is formed which separates on standing after about 1 hour. A mixture of the suspension of lampblack in water with 120 parts of white paint mixed as described above was coated on paper and dried and gave a much lighter shade of grey and was nonuniform.

The hydrolysis products can be prepared from the com pounds of this invention accordingly:

EXAMPLE A Triethylureidoammonium Chloride Triethylamine cyanoimide (4.0 g., 0.28 mole) was dissolved in 16 percent hydrochloric acid (25.8 ml.) and heated at 50-54 C. for 18 hours. The reaction mixture was evaporated to dryness (0.1/.L/50 C.) to give a white crystalline solid (5 .50 g.).

H n.m.r. spectrum: (D 0 solution. tetramethylsilane internal standard).

-r Assignment Weight 8.62 (triplet) CH: 9

Infrared spectrum: )t- 2.9 3.05;.

max.

EXAMPLE B Trimethylureidoammonium Chloride Trimethylamine cyanoimide (4.0 g., 0.04 mole) dissolved in 7 percent hydrochloric acid (35 ml.) was heated at 50-54 C. for 18 hours. The reaction mixture was evaporated to dryness (50 C./1 mm.) to give a white crystalline solid (6.55 g.) which was dissolved in absolute alcohol. The alcohol solution was filtered and evaporated to dryness (50 C./l mm.) to give white needles (6.0 g., 98.5 percent). A 1 g. aliquot of this product was recrystallized twice from alcohol and ether to give purified white needles (m.p. l59l60 C. with gas evolution). A water solution of this compound was slightly acidic.

Anal. Calcd. for C,H,,N,Cl0.

526 (single peak) H,O (from exchange of NH, with 0,0 1

Infrared spectrum: Ax; 2.97 1,, 3.05;, 3.12;, 3.20;; (NH

and/or NH 3.32;. 3.43 (saturated C-H); 5.87 (C=O);

EXAMPLE C Ammonium Salt of Pseuoureido Trimethylammonium Chloride An aliquot (5 g.) of the crude hydrolysis product described in Part B was dissolved in absolute alcohol 100 and excess an hydrous ammonia was added. The white salt which precipitated was separated and recrystallized twice from methanol and ether (m.p. l62.8l63.2 C.). An aqueous solution of this salt was slightly basic.

Anal. Calcd. for C H N.CIO:

C, 28.15; H. 8.36; N. 32.83; C 20.78 Found: C. 28.43; H. 9.04; N, 33.07; Cl. 20.95

(deuterium oxide solution.

tetramethylsilane internal standard).

H n.rn.r. spectrum:

1 Assignment Weight 6.59 (single peak) CH, 3 5.20 (single peak) H,O (from exchangeable 2 protons) Infrared spectrum: XQ' 'QZSMr, 3.0m. 3.17;; (NH,, NH or NH, 3.38;; (saturated C-H); 5.84 (possibly CPO); 6.13 6.41 (NH, and/orc -m; 1.13,

The embodiments of the invention in which an exclusive.

property or privilege is claimed are defined as follows:

I. A zwitterionic compound of the formula wherein R is alkyl of up to 10 carbon atoms or cycloalkyl of four to six carbon atoms, R and R taken separately, are alkyl of up to 10 carbon atoms, cycloalkyl of four to six carbon atoms, phenyl or naphthyl; R and R taken together, is a divalent alkylene group of four to six carbon atoms; and R, R and R taken together. is CH=CHCH=CHCH=.

2. The compound ofclaim 1 wherein R, R and R are ethyl.

3. The compound of claim 1 wherein R, R and R are methyl.

4. The compound of claim 1 wherein R is cyclohexyl and R and R are ethyl.

5. The compound of claim 1 wherein R, R and R are n-octyl.

6. The compound of claim 1 wherein R, R and R taken together is CH=CHCH -=CHCH=.

7. The process for preparing a compound of claim 1 comprising heating in an inert solvent at a temperature of 0-l 00 a. a tertiary amine of the formula 

2. The compound of claim 1 wherein R, R1 and R2 are ethyl.
 3. The compound of claim 1 wherein R, R1 and R2 are methyl.
 4. The compound of claim 1 wherein R is cyclohexyl and R1 and R2 are ethyl.
 5. The compound of claim 1 wherein R, R1 and R2 are n-octyl.
 6. The compound of claim 1 wherein R, R1 and R2 taken together is -CH CH-CH CH-CH .
 7. The process for preparing a compound of claim 1 comprising heating in an inert solvent at a temperature of 0*-100* C. a. a tertiary amine of the formula wherein R, R1 and R2 are as defined in claim 1, and b. cyanogen azide. 